Japan's Ohsumi wins Nobel for work on «self-eating» mechanism in cells

TOKYO. KAZINFORM - Japanese scientist Yoshinori Ohsumi won this year's Nobel Prize in physiology or medicine for elucidating mechanisms for autophagy, an intracellular process that degrades and recycles proteins, the Nobel Assembly at the Karolinska Institute said Monday.

The 71-year-old honorary professor at the Tokyo Institute of Technology revealed the mechanism of how autophagy begins, opening up the possibility of new treatments for illnesses including cancer, and Alzheimer's and Parkinson's diseases.

Ohsumi's discoveries "led to a new paradigm in our understanding of how the cell recycles its content. His discoveries opened the path to understanding the fundamental importance of autophagy in many physiological processes, such as in the adaptation to starvation or response to infection," Karolinska said in a statement.

"I'm truly honored," Ohsumi told Kyodo News by telephone upon being named the 25th Japanese to win a Nobel Prize and fourth to win the prize in physiology or medicine. "It's a little bit surprising for me that I am the single recipient."

The Fukuoka native follows Satoshi Omura, a Japanese scientist who shared the same prize last year with two other scientists.

At a press conference in Tokyo, Ohsumi said he started his research to do "what others don't." He underlined the importance of basic research, saying, "When I started the research, I was uncertain autophagy would be linked to issues concerning the life expectancy of human beings."

Autophagy, Greek for "self-eating," plays a housekeeping role by degrading abnormal or unnecessary proteins in cells. It is also a conserved self-digestive process, in which cells adapt to starvation by decomposing their own proteins and using them as new energy sources.

In 1988, Ohsumi, for the first time in the world, observed the process with an electron microscope by using a yeast cell and discovered how a cell degrades its own constituents and reuses them as energy in a vacuole. He also discovered key genes involved in the process of autophagy.

Prior to Ohsumi's research, the process had been roughly known since the 1950s.

Since its self-cleaning function is believed to be key for maintaining bodily health, recent studies have found that an abnormality in the autophagy process is connected to cancer, type 2 diabetes, and Alzheimer's and Parkinson's diseases.

Ohsumi said in the press conference that human lives are built on the recycling system, describing it as "an (important) element that supports lives."

Ohsumi conducted an experiment with mice and found that when the self-digestive process does not function in liver cells, the cells bloated and became cancerous. When he tested the same thing in the brain, old and abnormal proteins aggregated in nerve cells, leading to Alzheimer's and other neurodegenerative diseases.

Born as the youngest of four siblings in the city of Fukuoka in southwestern Japan, Ohsumi entered the University of Tokyo and finished a doctoral program before studying at Rockefeller University in the United States, where he was intrigued by budding yeast cells, which later led to his breakthrough in the understanding of autophagy.

Ohsumi then returned to Japan and as an assistant researcher at the University of Tokyo began studying budding yeast cells, before his successful observation of the autophagy process in 1988. He has been a professor at the Tokyo Institute of Technology since 2009.

Ohsumi's findings have also advanced research on the genes responsible for autophagy and his team contributed to the identification of most of the 18 specific genes essential to autophagy in yeast.

Masaaki Komatsu, a biochemistry professor at Niigata University, said research into autophagy had made little progress for some time since the phenomenon became known.

It was Ohsumi who made breakthrough by exposing its basic mechanism and links to diseases such as Parkinson's through his discoveries of relevant genes, Komatsu said. "To me, it was a matter of time before he won the prize."

Last year, Omura shared the Nobel Prize in physiology or medicine with Ireland-born William Campbell and China's Tu Youyou, after fellow Japanese Shinya Yamanaka won the same prize in 2012 with Britain's John Gurdon.

Ohsumi will receive prize money of 8 million Swedish kronor ($937,000) at a ceremony to be held in Stockholm on Dec. 10.

Source: Kyodo

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